Apparatus for stacking trusses



April 8, 1969 A. E. M GLINCHEY v I 3,437,216

APPARATUS FOR STACKING TRUSSES Filed June a, 196'? Sheet of a FIG! ' I a g -a- Q '2 .11 II Ifl lmmmlllulm L/J INVENTOR. ARTHUR E. MQGLINCHEY Wow ATTORNEYS April 8, 1969 Filed June 2, 1

A. E. M GLINCHEY APPARATUS FOR STACKING TRUSSES Sheet 2 of8 FIGQZA INVENTOR.

A TTORNEYS ARTHUR E. MQGLINCHEY p 1 ,19s9 A. E. M GLINCH EY 3,437,216 I APPARATUS FOR STACKING TRUSSES Sheet Filed June 2, 1967 INVENTOR.

' ARTHUR E. M; GL/NCHEY BY a W ATTORNEYS FIG.3

April 1969 I A. E. MGL|NCHEY 3,437,216

APPARATUS FOR STACKING TRUSSES Filed June 2, 1967 5 of s '1 l 1/4 L-52 3 \"II5 V 45 I8 I 5 1 ll 1 l Q E 49 l A A ARTHUR E. MQGLINCHEY A T TORNEYS S heet Filed June 2, 1967 FIG.9

FIG. 6

' INVENTOK ARTHUR E. MQGL/NCHEY BY 7 67 ATTORNEYS April 8, 1959 Filed June 2, 19 67 92 if XNVENTOR.

ARTH UR E. MQGLINCHEY ATTORNEYS I April 1969 A. E. MQGLINCHEY 3,437,216

APPARATUS FOR STACKING TRUSSES FiledJune z, 1967 sheet] 8 as INVENTOR. I ARTHUR E. MQGLINCHEY ATTORNEYS United States Patent 3,437,216 APPARATUS FOR STACKING TRUSSES Arthur E. McGlinchey, 1122 NE. 1st Ave., Fort Lauderdale, Fla. 33304 Filed June 2, 1967, Ser. No. 657,440 Int. Cl. B65g 57/00; B25j 3/00; B61b 13/00 U.S. Cl. 2147 8 Claims ABSTRACT OF THE DISCLOSURE The apparatus has a carriage reciprocatingly movable on a base between a truss receiving station and a stacking station. The carriage is moved by an endless drive chain supported between spaced sprockets on the base. A swing boom is mounted on the carriage to rotate approximately 90 through a vertical plane so that a truss disposed horizontally at the receiving station is lifted to a vertical position and so deposited at the stacking station. A lift hook retains the truss on the boom in juxtaposition to a trip bar. When the truss supported on the boom encounters the resistance offered by engagement of the truss with a stop, or a previously stacked truss, the trip bar is urged rearwardly. This rearward movement of the trip bar withdraws the lift hook by a multiplying mechanism to deposit the truss at the stacking station and actuates a clutching mechanism operatively connected between the carriage and the drive chain to reverse the direction of movement of the carriage without reversing the movement of the drive chain.

Background of the invention Trusses can be fabricated in all sizes, in many shapes and from a host of materials. For example, trusses can be fabricated from wood, in whole or in part, held together by metal connector plates, such as taught by US. Patent No. 3,212,694. After the trusses are assembled, they must be removed from the assembly area, stacked and bound together for shipment. As shown in US. Patent No. 3,255,943, devices have been provided for sliding the truss from the fabricating machine onto a conveyor along which it may be transported to the stacking area. However, when the trusses arrive at the stacking station they have theretofore been required to be lifted manually into either vertical or horizontal stacks where they could be strapped, or otherwise bound, together for shipment.

This requires considerable expenditure of labor and energy. Moreover, when carelessly handled in a position transversely to their intended orientation, any excessive flexural racking tends to loosen the means by which the truss components are joined.

Summary of the invention It is therefore the primary object of the present invention to provide a truss stacking device which is capable of raising a truss from a horizontal to a vertical position Without excessively flexing the truss transversely of its intended in-use orientation.

It is another object of the present invention to provide a truss stacking device, as above, which will stack vertically oriented trusses in successive juxtaposition.

It is a further object of the present invention to provide a truss stacking device, as above, which, while it is capable of picking up, turning from horizontal to vertical orientation, transporting, and depositing a truss and thereafter returning to pick up another truss without human intervention or control, is nevertheless relatively uncomplex and economical to manufacture and operate.

These and other objects which will become apparent from the following specification are accomplished by means hereinafter described and claimed.

In general, a truss stacking device embodying the concept of the present invention has a base on which a carriage is reciprocally movable between a truss receiving station and a stacking locus. A swing boom is mounted on the carriage for approximately rotation in a vertical plane. This rotation lifts a truss from a horizontal to a substantially vertical position. Means are provided to rotate the boom as desired, preferably in response to movement of the carriage toward the stacking locus. A lift means is provided to retain the truss on the boom even when the boom is in its substantially vertical position.

An endless drive chain is mounted between sprockets on the base and is connected to the carriage by a unique clutch means which selectively engages one or the other of the two passes of the drive chain to move the carriage in either direction without changing the direction of movement of the chain drive.

The clutching mechanism is actuated by a bifurcated shift link which connects between a trip bar on the swing boom and the clutching mechanism. The trip bar, which is responsive to the stacking locus, also retracts the lift means by a unique multiplying mechanism.

One preferred embodiment is shown by way of example in the accompanying drawings and is described in detail without attempting to show all of the various forms and modifications in which the invention might be embodied; the invention being measured by the appended claims and not the details of the specification.

Description of the drawings FIG. 1 is a top plan view of a truss receiving station employing a pair of devices embodying the concept of the present invention to deposit trusses at a stacking locus;

FIG. 2 is an enlarged partial side elevation of a stacking apparatus taken substantially on line 22 of FIG. 1;

FIG. 2A is a continuation of FIG. 2 joinable at lines 11-]; and a'-b;

FIG. 3 is a partial side elevation similar to FIG. 2 with the swing boom rotated to its substantially vertical position;

FIG. 4 is an enlarged partial cross section taken substantially on line 44 of FIG. 2A;

FIG. 5 is a further enlarged cross section taken substantially on line 5-5 of FIG. 2;

FIG. 6 is a further enlarged partial top plan taken substantially on line 6-6 of FIG. 2;

FIG. 7 is an enlarged side elevation of the clutching mechanism depicted in FIG. 2A;

FIG. 8 is a vertical cross section taken substantially on line 88 of FIG. 7; and,

FIG. 9 is a horizontal cross section taken substantially on line 99 of FIG. 7.

Description 0 f a preferred embodiment Referring more particularly to the drawings, the subject truss stacking mechanism, indicated generally by the numeral 10, may be utilized in any number of ways. For example, it may be positioned intimately with a truss fabricating machine, or, as shown, it may be positioned in conjunction with a truss receiving station 11 located adjacent a truss fabricating area in which a plurality of truss fabricating machines are employed.

Depending upon the size of the trusses, and their configuration, it may be advantageous to use more than one stacking mechanism for each truss. The schematic representation of FIG. 1 discloses a conveyor 12 leading from one or more fabricating machines (an example of which may be found in US. Patent No. 3,255,943) to the receiving station 11. The laterally spaced rollers 13 on station 11 permit the representative truss .14 to move easily from the conveyor 12 onto the station 11. As shown, two laterally spaced stacking mechanisms and 18A may be operated simultaneously to raise the truss 1'4 from the receiving station 11 and stack it in vertical disposition on support pads 15 and 16 where a predetermined number may be strapped, or otherwise bound, together for shipment.

Irrespective of the number of stacking mechanisms employed they may all be constructed according to the same concept. As best seen in FIGS. 2-5, the base 18 presents a pair of parallel, upwardly facing track members 19 and 20. As depicted in FIG. 1, the track members v19 and 20 extend transversely adjacent the receiving station 11, beneath the truss 14 and slightly beyond the location where it is desired to deposit the trusses.

A pair of spaced dollies, 21 and 22 rigidly interconnected as by the four parallel tubular side rails 23, 24, 25 and 26 form a carriage, indicated generally by the numeral 28, movably mounted on the tracks 19 and 20 by wheels 29, 30, 31 and 32. A pair of bogie wheels 33 and 34 are also carried on each dolly for engagement with the underside of the track members 19 and 20 toprevent the carriage 28, or any part thereof, from lifting upward- 1y off the base 18.

A swing boom 35 is mounted on carriage 28 for vertical movement about a horizontal pivot shaft 36 supported on journal plates 38 and 39 fixed to the tubular frame members 23, 25 and 24, 26, respectively, forwardly of the front dolly 21.

The lift boom 35 comprises a pair of tubular frame members 40 and 41 secured to the pivot shaft 36, as by gusset plates 42 and 43 and themselves trussed from the kingpost 44 which extends perpendicularly of the frame members 40 and 41 to which it is secured. Struts '45 and 46 extend from the ends of the frame members 40 and 41 to truss them for the loads they are to lift. For convenience, the strut may be provided with a turnbucklelike tensioning device 48 to adjust the length thereof and hence the disposition of the frame members 40 and 41.

An axle 49 is fixed to the apex of the struts 45 and 46 and carries a pair of cam followers 50 and 51 which cooperate with a pair of cams 52 and 53 mounted on the base .18 by which raising of the lift boom is directed.

One or more trip bars 54 and 55 are pivotally mounted on the frame members 40 and 41, as by pin '56, to contact the truss to be lifted thereby, and a lift hook 58 extends outwardly from between the trip plates '54 and 55. The lift hook 58 is carried on a swing arm 59, also pivotally carried on the frame members 40 and 41, as by pin 60. The operation of the trip plates to withdraw the lift boom from the truss, and the operatio of the lift hook 58 to release the truss are more fully hereinafter explained in conjunction with the explanation of the movement of the carriage 28.

Movement of the carriage 28 is powered by a motor 61 mounted on the base 18. The motor 61 (-FIG. 2A) is connected, through a gear reducer 62 and a chain '63, to a driven sprocket 64 nonrotatably mounted on shaft 65 which is journaled on the rearward portion of base 18. A drive sprocket 66 is also n-onrotatably mounted on shaft 65. Aligned with drive sprocket 66 and spaced forwardly thereof a slight distance greater than the distance the carriage 28 is intended to move along the base 18 is an idler sprocket 67 (FIG. 2) rotatably mounted on a shaft 68 supported by base 18. A continuous drive chain 69 is mounted between the drive and idler sprockets 66 and 67, respectively. The drive chain 69- is operatively connected to the carriage 28 through a unique clutching means, indicated generally by the numeral 70, such that without requiring reversal of the motor, the carriage may be moved forwardly or rearwardly along the base 18, as required to stack the trusses. As best seen in FIGS. 79, the clutch mechanism is secured to the carriage 28 by a hanger 71 attached to and depending from the side rails 23 and 24. Attached to, and spaced outwardly of the hanger 71 is a guide plate 72 which is positioned between the upper and lower passes 73 and 74, respectively, of the drive chain 69. A shift plate 75 is carried between the hanger 71 and the guide plates 72 for sliding movement between a upper position not shown, and the lower position depicted in FIGS. 7 and 8.

In sliding to the lower position, the shift plate 75 engages a lower support arm 76 pivotally mounted to bracket 78 on hanger 71, as at pin 79, to withdraw the engaging teeth'80 on lower arm 76 arcuately downwardly and away from the receiving notches 81 in the lower side of the guide plate 72. This downward swinging movement of the engaging teeth must be of sufli-cient magnitude to withdraw them from engagement with the links in the lower pass 74 of drive chain 69.

During this downward sliding of shift plate 75 the engaging teeth 82 o an upper support arm 83, similarly pivoted on bracket 78 by pin 79, swing arcuately downwardly. The downward movement of teeth 82 is effected by a pair of compression springs 85. Each spring 85 encases a pin 86 which is supported from the shift plate 75 and extends upwardly through a slotted opening 8-8 in the support arm 83, the spring extending between a head, or nut, 89, and a float bar 90 slidably carried on a pair of pins 86 at the upper side of the upper support arm 83. By the use of the float bar 90 the pivotal movement of the support arm 83 will not bind, or be bound, by accidental entrapment of the spring 85 between the support ram 83 and the pin 86.

Conversely, when the shift plate moves upwardly from the lower position depicted in FIGS. 7 and 8 to the uppermost position an identical arrangement of compression springs 91 on pins 92 between nut 93 and float bar 94 biases the teeth 80 on support arm 76 toward engagement with the receiving notches 81 on guide plate 72. The engagement of the shift plate 75 with the upper support arm 83 withdraws the teeth 82 from the receiving notches 84 on guide plate 72. Here too, the upward swinging movement of the teeth 82 must be of sufiicient magnitude to withdraw them from engagement with the links in the upper pass 73 of drive chain 69.

It must here be emphasized that the opposed teeth 80 and 82 are not directly carried on the shift plate 75 even though they appear to, and often do, move in direct response to movement of the shift plate. The teeth are floatingly carried, as described, so that as they are biased toward the guide plate 72 they will not jarn if the position of the individual links on passes 73 and '74 of the drive chain 69 is such that the teeth would not clear the opening of the links.

With the afore-described unique clutching means 70 it is possible to reciprocate the carriage back and forth along the base 18 even though the motor 61 only drives the chain 69 in one direction. As viewed in FIGS. 2 and 2A with the upper pass 73 moving to the left, in the direction of the arrow, the lower pass 74 will automatically be moving to the right. Accordingly, the direction in which the carriage 28 moves will depend upon which teeth engage the chain 69.

In order to accomplish an orderly stacking of trusses on support pads 15 and 16 it has been found most desirable if each successive truss is deposited in juxtaposition with the preceding truss. Accordingly, the forwardmost position of the carriage 28 is not constant but rather varies with each truss stacked. The following construction incorporates the unique shift actuating concept which accomplishes the desired result. 7

One end of a shift lever 95 is swingably supported on the hanger 71, as at 96. The other end of the shift lever 95 has a pair of opposed cam surfaces 98 and 99 which engage a cam follower 100 secured to the shift plate 75. The cam follower 100 extends from the shift plate 75 through a slot 101 in the hanger 71 to its position between the cam surfaces 98 and 99.

As best seen in FIG. 7, the cam surfaces 98 and 99 are generally angularly disposed with respect to the Swing radius of the shift lever 95 so that movement of the lever 95 through an arc of only a relatively few degrees shifts the plate 75 between its uppermost and lowermost positions.

With the shift plate in its lowermost position, as depicted, the upper teeth 82 engage the upper pass 73 of the drive chain, and the carriage is moved forwardly. To reverse the direction of the carriage a bifurcated shift link connects between the shift lever 95 and the trip plates 54 and 55. The first section 103 of the shift link is mounted on the carriage 28 for independent, generally axial, translation. The rearmost end of section 103 is connected, at pin joint 104, to an ear 105 fixed to, and extending generally transversely of, shift lever 95. The forward end of section 103 is restrained against any, but axial, movement. As shown, a collar 106 may be inserted in, or attached to, section 103 and be slidingly received over pivot shaft 36.

The second section 108 of the bifurcated shift link is pivotally connected, at 109, to the first section 103 from which it extends outwardly of, and is connected to, trip plates 54 and 55 by pin 110.

At this point in the description understanding is augmented by an explanation of the operation of the device. A truss 14 is moved horizontally along conveyor 12, by hand or power, until it comes to rest on the receiving station 11, as shown in FIG. 1. When a truss is so positioned, the motor 61 is actuated, the teeth 82 on upper support arm 83 engaging the links on the upper pass 73 of drive chain 69 and the teeth 80 on the lower support arm 76 having been withdrawn from the links on the lower pass 74 on completion of the cycle as hereinafter more fully described. Actuation of the motor 61 causes the upper pass 73 of chain 69 to move in the direction of the arrow in FIGS. 2 and 2A designated as forward motion, and the engagement of the clutching mechanism 70 with upper pass 73 causes the carriage 28 to move along base 18 in the same direction. This forward motion of carriage 28 almost immedately brings the wheel-like cam followers 50 and 51 into contact with cam surfaces 52 and 53. As the cam followers 50 and 51 move upwardly and forwardly along the inclined cams 52 and 53, the swing boom 35 is rotated about pivot shaft 36. This rotation of the swing boom 35 raises the truss 14 off the receiving station 11, and a counterweight 111 carried on the boom 35 forwardly of the pivot shaft 36 alleviates the forces required to accomplish this objective.

It will be observed that although the weight of the truss 14 is transferred from the rollers 13 at receiving station 11 onto the trip plates 54 and 55 as the swing boom 35 begins its rotation, the trip plates 54 and 55 nevertheless remain inclined with respect to the frame members 40 and 41. This inclination results from the fact that the second section 108 of the bifurcated shift link is constrained from axial movement by engagement of collar 106 with shaft 36 so long as it angularly disposed with respect to the first section 103.

The lift hook 58, because swing arm 59 is attached to the trip plates 54 and 55 by multiplying strut 112, also remains projected outwardly of the trip plates 54 and 55. Thus, as the boom 35 continues its rotational ascent the truss can slide downwardly along the plates 54 and 55 no further than the lift hook 58, even when the boom reaches the vertical-most position best seen in FIG. 3. So supported, the truss is carried forwardly by movement of carriage 28 until it reaches a stop, or a previously deposited truss 14A.

Contact of the supported truss 14 with either the previously stacked truss 14A or a stop not shown applies rearwardly directed pressure against the trip plates 54 and 55. With the lift boom 35 in the vertical position (FIG. 3) the two sections 103 and 108 of the bifurcated shift link are axially aligned so that the trip plates are not 6 restrained from rotating rearwardly about their pivot 56. This rotation accomplishes several simultaneous results.

The axially rearward translation of the two portions 103 and 108 of the shift link pivots the shift lever about its swinging support 96. As the shift lever 95 pivots, the interaction of the cams 98 and 99 with follower 100 moves the shift plate 75 immediately from the lowermost position depicted in FIGS. 7 and 8 to its uppermost position. The teeth 82 are instantaneously disengaged from the links on the upper pass 73 of chain drive 69 to halt forward movement of the carriage 28. At the same time, the springs 91 bias the teeth 80 on the lower support arm 76 toward engagement with the links on the lower pass 74 of drive chain 69. The floating support of teeth 80 permits them to engage the lower pass 74 of drive chain 69 only when the links are properly oriented. As soon as they are engaged, the carriage 28 is moved rearwardly.

The pivotal rearward movement of trip plates 54 and 55 which actuated the clutch mechanism 70 to reverse the direction of movement of carriage 28 also withdraws the lift hook 58 with respect to the trip plates 54 and 55 to deposit the truss 14 on support pads 15 and 16. The withdrawal of the lift hook 58 is accomplished by the relative locations of the pivot point 56 for trip plates 54 and 55 and the pivot point 60 for the swing arm 59 as well as the location of the multiplying strut 112.

For example, with the length of the trip plates 54 and 55 between the pivot 56 and the point at which the lift hook 58 extends outwardly therefrom being approximately twice as long as the swing arm 59 between its pivot 60 and the hook 58, and with the multiplying link 112 attached between the swing arm and the trip plates approximately one-third of the distance between the pivot 60 and the hook 58, the rearward movement of the hook 58 will be approximately twice the rearward movement of the trip plates 54 and 55. Hence, if the trip plates are moved rearwardly three inches, the hook will be moved rearwardly six inches. That is, three inches more than the rearward movement of the trip plates 54 and 55, so that if the hook 58 had originally extended three inches beyond the trip plates 54 and 55, this movement would completely withdraw the hook 58 so that the truss 14 could drop onto the support pads 15 and 16.

As the carriage 28 moves rearwardly along the base 18, the followers 50 and 51 engage upper cams 114 and 115 in opposition to earns 52 and 53, respectively, which counter-rotates the lift boom 35, against the force of counterweight 111, from a vertical to a horizontal disposition. The bifurcation of the shift link about pin 109 permits the two sections thereof to return to their angular disposition which not only raises the trip plates 53 and 54 from the frame members 40 and 41 but also extends the lift hook 58 to its protracted position outwardly of the trip plates.

As the carriage reaches its rearwost position, a feeler shaft 116 is pivoted on the rear of ear 105 and slidingly supported on dolly 21 engages a limit stop 118 on frame 18. Engagement of the feeler 116 with the limit stop 118 as the carriage 28 is moving rearwardly applies f0rwardly directed pressure to the ear 105 which pivots the shift lever 95 about its swinging support 96 such that the cams 98 and 99 interact with follower 100 to move the shift plate 75 from its uppermost position (not shown) to the lowermost position depicted in FIGS. 7 and 8. The teeth 80 are thereby instantaneously disengaged from the links of the lower pass 74 of drive chain 69 to halt rearward movement of the carriage 28. At the same time, the springs 85 bias the teeth 82 on the upper supportarm 83 toward engagement with the links on the upper pass 73 of chain drive 69.

As the teeth 80 disengage, a cam 119 carried on feeler shaft 116 actuates a limit switch 120 to turn off the motor 61. The forward swing of shift lever 95 and the attendant forward translation of the first section 103 of the bifurcated shift link are not restricted by the angular orientation of the second section 108 inasmuch as section 108 is pivotally secured to section 103, at 109, and to the trip plates 54 and 55, at 110.

Reactivation of the motor 61 can be effected automatically by the positioning of the next truss on receiving station 11, or, if preferred, manually. In either event, if the teeth 82 have not already engaged the links on the upper pass 73 of drive chain 69, as soon as the motor begins to drive the chain 69 the floating mount of the teeth 82 will cause them to engage the chain and the carriage 28 will move forwardly to begin the cycle anew.

It is thus apparent that a truss stacking apparatus embodying the concepts of the present invention accomblishes the object thereof.

I claim:

1. A truss stacking device comprising, a base, a carriage movable on said base between a truss receiving station and a stacking locus, an endless drive chain which travels unidirectionally around spaced sprocket means on said base so that one pass of said chain always travels in one direction and the second pass of said chain always travels in the opposite direction, clutch means secured to said carriage for selectively engaging one or the other of said passes to move the carriage toward or away from said stacking locus, a swing boom mounted on said carriage for rotation in a vertical plane from a substantially horizontal position to a substantially vertical position, means to rotate said boom, lift means on said boom to support a truss thereon when said boom is oriented in the substantially vertical position, and trip means responsive to said stacking locus to withdraw said lift means from the support of said truss and to effect reverse movement of said carriage by actuation of said clutch.

2. A truss stacking device, as set forth in claim 1, in which said clutch mechanism has separate teeth means for engaging each said pass, and separate means for moving said teeth into and out of engagement with said drive chain.

3. A truss stacking device, a set forth in claim 2, in which spring means continuously bias said teeth toward engagement with said drive chain and a shift plate is movable between alternate positions whereby to maintain one or the other of said separate teeth means out of engagement with said drive chain.

4. A truss stacking device, as set forth in claim 3, in which a cam means is operated by said trip means to move said shift plate in response to said stacking locus.

5. A truss stacking device, as set forth in claim 1, in which said trip means is pivotally mounted on said lift boom, restraining means being attached to the said first means and said clutch means, said shift link having two sections pivotally joined, the first section operatively secured to said clutch means, the second section operatively secured to said trip means remotely of the pivotal mount by which said trip means is fastened to said swing boom, restraining means being attached to the said first section to permit only axial translation of said first section at least at the pivotal juncture of said first and second section.

6. A truss stacking device, as set forth in claim 5, in which the first and second sections of said bifurcated shift link are substantially axially aligned when said swing boom is rotated to its substantially vertical position.

7. A truss stacking device, as set forth in claim 6, in which the length of said second section of said bifurcated shift link is such as to separate said trip means from said lift boom remotely of the pivot mount by which said trip means is fastened to said lift boom.

8. A truss stacking device, as set forth in claim 1, in which said trip means is mounted on said swing boom by a pivot spaced remotely of the rotational mount of said swing boom to said carriage, said lift means comprising a lift hook secured to and extending outwardly of a swing arm, said swing arm pivotally mounted on said swing boom medially of said pivot and rotational mount such that said lift hook is extensible outwardly of said trip means and retractible with respect thereto, a multi plying strut connecting between said trip means and said swing arm.

References Cited UNITED STATES PATENTS 2,800,992 7/1957 Kuper 214-7 X 2,932,415 4/1960 Brown 2l482 3,050,198 8/1962 Schmunk a a1 214 7 X 3,279,664 10/1966 Lynch 2147X 3,326,547 6/1967 Walters etal.

3,373,882 3/1968 Forest.

GERALD M. FORLENZA, Primary Examiner.

R. J. SPAR, Assistant Examiner.

US. Cl. X.R. 104-172; 2l4-1 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,437,2l6 April 8 1969 Arthur E. McGlinchey It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 47, "theretofore" should read heretofore Column 7, line 40, "a", second occurrence, should read as Column 8, lines 3 and 4, restraining means being attached to the said first means" should read and a shift link is connected between said trip means Signed and sealed this 21st day of April 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. E.

Attesting Officer Commissioner of Patents 

